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April 25, 2005

Good Question: Worry About Aluminum in Antacids, Not in Aspirin

by Sam Savage

Question: I have read that enteric-coated aspirin contains aluminum. Can you tell me if this is true? Can you tell me what "enteric coating" is made of? And can you tell me what evidence there is that ingesting aluminum regularly may cause health problems? This seems to me to be especially important now that many people are taking baby aspirin daily on the advice of their cardiologists. - Aku, also known as Ed Oppenheimer, over 50 years old, Santa Fe

Answer: Navigating the dos and don'ts of aluminum consumption can be downright confusing.

Aku, a textile artist, has been hesitant to follow his cardiologist's suggestion to take aspirin regularly because of unresolved concerns about the presence of aluminum in aspirin.

"It's possible it's another big mistake by the medical profession," Aku said, of the common advice to take aspirin.

He refuses to take it. Instead, he uses ginkgo, an herb with blood-thinning qualities.

"It seems to do the job as well as aspirin," he said.

In large quantities, aluminum can be toxic, especially for people with kidney problems.

Michael Lacey, director of pharmacy at St. Vincent Regional Medical Center, remembers taking a set of aluminum pots and pans back to the store because he was concerned that eating food cooked in them would dump too much aluminum into his bloodstream. "The fear is dementia and Alzheimer's can be caused by aluminum," he said.

But when it comes to aspirin, he's not worried. To him, a more serious concern lies in antacids with aluminum, which carry a far bigger dose than aspirin.

"The risk of aluminum toxicity resulting from the enteric coating in a person without kidney disease is zero," Lacey said. "The benefit of taking aspirin in a male over 50 years old has been shown repeatedly to reduce heart attack and stroke in this population. There is no question that, from a health perspective, it is in this person's best interest to take the aspirin."

Lacey explained the ins and outs of enteric-coated aspirin.

Aspirin is known to cause stomach bleeding. Enteric coatings, some of which contain aluminum hydroxide, are applied to tablets to allow aspirin to bypass the stomach and dissolve in the small intestine, he said. The coatings are made of starch-like chemicals that come from wood. Aluminum hydroxide is sometimes used as a component of the dye for the coating. In enteric-coated aspirin, it's known as FD&C #6 Aluminum Lakes, he said.

Aluminum is everywhere. It is one of the most plentiful elements in nature. Drinking water, fruits and vegetables, fish, meats, cooking utensils, cosmetics and even cheeseburgers add to the daily dose. The average person consumes 2 to 8 mg per day. Automatically, the body flushes most of it out.

"When aluminum is present as an ingredient in an enteric-coating formulation," Lacey said, "it would be in extremely small amounts, similar to aluminum content in the diet. I don't think you'd get one- tenth of one milligram from the coating on aspirin."

By comparison, some antacids contain up to 100 mg of aluminum per dose, he emphasized.

For a healthy person, large amounts of the metal are the problem. For a pregnant woman or a person with poor-functioning kidneys, smaller doses can have a stronger effect.

"There is evidence that ingestion of large quantities of aluminum can cause toxicity in humans, particularly when the quantity ingested exceeds the body's capacity to eliminate it," Lacey said.

For a deeper discussion, he recommended emedicine.com on the Internet.

Aluminum toxicity was originally described in the mid-to-late 1970s in a series of patients in Newcastle, England, and remains a rare condition, according to the site. Excess aluminum is deposited in various tissues, including bone, brain, liver, heart, spleen and muscle.

Since the role of aluminum in disease has been identified, more attention has been paid to the element. Aluminum causes an oxidative stress within brain tissue, leading to the formation of Alzheimer- like neurofibrillary tangles. Excess aluminum has been shown to induce anemia. Children might have varying degrees of growth retardation.

Recent case reports have implicated the use of aluminum- containing antacids during pregnancy as a possible cause for abnormal fetal neurologic development.

The signs and symptoms of aluminum toxicity may include muscle weakness, bone pain, multiple non-healing fractures, acute or subacute alteration in mental status and premature osteoporosis. These patients almost always have some degree of renal disease.

According to the Web site, medical staff should educate pregnant and breastfeeding females, and any patient with compromised kidney function, about the potential dangers of the use and overuse of aluminum-containing antacids. A safe alternative includes calcium carbonate, such as that found in Tums.